|
TennisOne Lessons 
Understanding the Kinetic Chain David W. Smith, Senior Editor TennisOne A competitor of virtually any sport would have to be living under the proverbial rock to not have heard the phrase, “Kinetic Chain” as it applies to movement and motion. Any sport that involves hitting an object such as a tennis ball, golf ball, baseball, hockey puck, or badminton shuttlecock will employ the Kinetic Chain in some aspect, especially when speed, distance, pace, and overall power is desired.
In tennis, the act of interacting with a tennis ball is very dynamic; it involves not only racquet head speed elements but spin, angle of reflection, and the quantity of movement by the player. Unfortunately, in tennis as in other sports, there are ways to execute shots relatively successfully within the realm of mediocrity that can mislead players into believing they are improving. And they are, up to a point, because they ‘successfully’ got a ball over the net and landed it in the court. However, this limited skill can and often does prevent a player from reaching anything but the most pedestrian skill levels and that player may very well remain at that level for the rest of his or her tennis life. We see it every day — players who have been playing tennis for decades yet continue to play at a level that is below their physical abilities and certainly below their aspirations and desires. Understanding the Kinetic Chain is a very key component for players who wish to continue to progress past those levels that are associated with stagnation or simply mediocrity. We often hear players actually verbalize their sense of frustration with themselves when they watch others who are no more ‘gifted’ physically than they are, move past them. “How did John get so good?” “I remember I used to kill that player a year ago.” “I wish I could play as well as Cindy.” Sound familiar? Well, the reason why most players advance and other players stagnate is in many ways associated with the understanding—or lack of understanding—of the Kinetic Chain. So it will serve everyone, especially those who are having difficulty making advancements in their game, to pay attention to some of the key elements of the Kinetic Chain as well as to recognize some of the faulty patterns that many players incorporate into their games that prevent a greater capacity to play tennis at higher levels.
Overview The Kinetic Chain is basically based on the concept that our bodies move from the ground up. Most people know this but that is where their clear understanding of the Kinetic Chain stops. Beginning with the feet, the Kinetic Chain is a series of movements of body parts or what is often referred to as ‘segments,’ that when fired in sequence, work in harmony to not only produce a desired swing speed, but also an opportunistic swing path. This series of movements as a whole provides not just power but also control. Let’s face it; many people can swing a racquet hard enough to create high ball speeds. The problem becomes obvious when a player uses the Kinetic Chain improperly: The ball not only goes out, but it goes out exponentially farther when the player tries to hit harder. Yet, we watch skilled players hit—from the pros to top rated juniors to high level club players—and they can hit with seemingly great control at speeds that are usually much faster than what lower level players can generate. So, not only is the understanding of the Kinetic Chain critical to the ability to control more power, it in-and-of-itself can increase available power through greater efficiency. From the feet, the body movements include the legs, the hips, the upper body, the shoulder plane, the arms, the hands, and finally the racquet itself. Misfire any one of those segments and the likely result will be an errant, uncoordinated shot. If we can picture a whip being cracked, (think Indiana Jones!), we can grasp this concept of speed being generated by the hand holding the whip – when used correctly, the tip of the whip, when cracked, creates so much speed that it breaks the sound barrier. A whip is a flexible rope that can move in almost any direction. Yet, in order to make the end crack, we must move that flexible cord in a fairly precise way. Our body is somewhat like that whip. However, we are not nearly as flexible, and our flexible joints are limited in terms of direction of movement as well as in range of motion within that movement. So we look at the biomechanical motion of the human body and over the years have come up with better and better ways to successfully, and within the concept of controlled manipulation, hit a tennis ball with greater effect (think spin, power, and control). Kinetic Chain Elements The first thing that one must understand about the Kinetic Chain is that while one segment often follows another in specific sequence, there are degrees in which the previous segment will diminish it’s contribution to the overall motion allowing the following segments to accelerate. This is a bit confusing so I’ll describe it using the tennis example: If I start to swing with my hips rotating around as with a typical angular momentum rotation, my racquet will start to come around with this rotation. Angular Momentum is the concept of swinging around a pivot point rather than moving the racquet in a linear line towards a target. Angular momentum would describe any proper rotational swing such as a tennis forehand stroke, a golf swing, or a baseball player swinging a bat. Linear swings would be similar to the motion of bunting a baseball, putting a golf ball, or hitting a block volley in tennis. If all we do is continue this rotation with no reduction of hip rotation, the arm must then be held back within the stroke and thus the racquet can only hit the ball at the speed of this hip rotation. Since the hips can only rotate at a relatively slow speed, (compared to what we can do, say, with our arms or hands), we will hit the ball with only this relatively slow speed. Not a very efficient or effective way to propel the ball. I use this example because this is often what beginners tend to do when they know nothing about tennis strokes and they are trying to control direction. Using gross musculature, players feel they can indeed control direction simply because there are a) very few ‘moving parts’ associated with this type of swing, and b) this swing is slow enough to feel like they have some semblance of control. Jimmy Connors was often used as an example of this type of swing (on the forehand side). However, he was far from a beginner! Yet, in reality, his stroke had other factors that allowed him to hit bigger than what this swing pattern alone would permit, as I’ll discuss.
Slowing Down the Segments In order to allow the remaining segments to build upon the initial Kinetic Chain movements, the early segments must slow down at some point to allow the next segments to become involved and to contribute to a more substantial stroke. Thus, at the contact phase of a stroke such as a forehand or backhand the player will need to slow the lower body segments down so the upper body can ‘catch up’ and, just like our analogy of cracking a whip, the final segment, the racquet, can be whipped into the ball with great speed. When the legs and hips slow down, the upper body segment, (the shoulder plane) can accelerate; think of the lower and upper body segments working like a coiled spring that has a great deal of potential energy stored when it is indeed coiled. This is one reason the open stance has become such a staple on the forehand and even on the backhand strokes. An open stance creates greater torque between the upper and lower body segments. However, now the upper body needs to slow down to allow the arm to begin its acceleration phase. The arm (or arms if we are using two-handed strokes) starts to come around the body in this continuous passage of segment acceleration. Finally, the racquet catches up and moves through the hitting zone with amplified speed. With serves and overheads, we have an added element to the chain, ‘pronation,’ that becomes the last moving segment of the Kinetic Chain as it applies to these strokes. To examine this aspect more closely, one only needs to do a simple experiment on the court to see why these events happen in the sequence I’ve just described Experiment: Stand in the middle of the court on the baseline or service line and drop feed a forehand to yourself. After you take your racquet back (loop or straight back, it doesn’t matter), swing to the ball…but don’t stop your hips, let them keep rotating around as you continue to swing with your normal arm motion. If you do this as described you will hit the ball so far to the left (if you are right-handed) that you will feel the need to decelerate the arm and racquet to simply control the ball towards the court. This is what a lot of players do inadvertently and end up having to literally “push” the ball towards the target in a linear swing path because their body recognizes that they will indeed pull the ball out wide. We see this action a lot with lower level servers, especially those who first learned to serve with the eastern forehand grip facing the net. The eastern grip forces the player to swing forward in line with the target, leading with the hitting elbow then the arm pulling down to generate some power, basically eliminating the ability of the player to use the last segments of the Kinetic Chain, namely the arm release and pronation elements, that create both ideal racquet head speed as well as proper spin and an ideal racquet head orientation.
Wrist The role and use of the wrist has been debated and discussed a great deal in recent years. With the semi and full western grips on forehands, we see the racquet laid back so far that it appears there is some wrist flexion to the ball during the last segment of the Kinetic Chain. While I would agree that there is indeed some action of the wrist among high level forehands, the conscious action or use of the wrist by players trying to develop a skilled forehand (or backhand) would be ill advised. The reason is that intentional use of the wrist changes the racquet face during the most critical moment of any swing: the contact. While the use of the wrist certainly can increase the Kinetic Chain’s action in creating high racquet head speed, the ability to control this ever-changing racquet face on a consistent basis is extremely difficult if not impossible, especially as players increase their overall swing speed when accompanying the use of wrist flexion. What we actually see is more of what is called radial and ulna deviation…or a tilting of the wrist in the last segment as a pro is hitting the ball. This action increases not the forward motion of the racquet but the action of the racquet brushing up. This forearm deviation should not be confused with pronation which is also known as ‘internal rotation’ of the forearm. Again, the conscious action even of radial/ulna deviation is not recommended for players who are working to develop an advanced forehand foundation. Conclusion Understanding this relationship of the Kinetic Chain and the associate motions of the wrist, the forearm, and the timing of each segment, can greatly increase a player’s speed in the development of effective strokes. Learning to avoid such elements as over rotation and wrist movements will help prevent bad habits or swing elements that reduce the effectiveness and consistency of a player’s shot. Your comments are welcome. Let us know what you think about Dave Smith's article by emailing us here at TennisOne .
|
Your comments are welcome. Let us know what you think about this article by